VNX Family: Used capacity showing more in a pool than the hosts for luns (User Correctable)
This article applies to
This article does not apply to
This article is not tied to any specific product.
Not all product versions are identified in this article.
Symptoms
Customer added 6 luns added of 4 tb each, means 24tb equal to 24576 GB. but used capacity showing 25152 GB, difference is of 500GB.
Cause
This is because of lun overhead. Virtual Provisioning stores both user data and some metadata within the same slices and so this metadata will add to the capacity consumed by the LUNs.
Resolution
For 1 Tb you need to remove 21GB, for 500GB you need to remove 11GB and for rest 300GB you need to remove 9GB and sum them all up.
For 1 Tb it will take around 21 GB overhead.
As we have 6 lun of 4 tb then it is equal to 24 tb so 24* 21Gb = 504GB
For 1 Tb it will take around 21 GB overhead.
As we have 6 lun of 4 tb then it is equal to 24 tb so 24* 21Gb = 504GB
Additional Information
Examples of the overhead for VNX are shown below:
|
LUN Size |
VNX Release 32 (1 GB slice size) |
VNX with MCx (256 MB slice size) |
||
|
User Capacity |
Overhead (GB) |
Overhead (%) |
Overhead (GB) |
Overhead (%) |
| 100 GB | 5.00 | 4.76% | 3.00 | 2.91% |
| 500 GB | 14.00 | 2.72% | 10.25 | 2.01% |
| 1 TB | 28.00 | 2.66% | 20.25 | 1.94% |
| 16 TB | 412.00 | 2.45% | 302.75 | 1.81% |
| 64 TB | 1,642.00 | 2.44% | 1,206.75 | 1.81% |
| 256 TB | 6,562.00 | 2.44% | 4,823.00 | 1.81% |
Affected Products
VNX2 SeriesProducts
VNX1 Series, VNX2 SeriesArticle Properties
Article Number: 000061838
Article Type: Solution
Last Modified: 07 Nov 2025
Version: 3
Find answers to your questions from other Dell users
Support Services
Check if your device is covered by Support Services.